Charles E. Perkins’ invention of mobile IP enables mobile devices
to be moved between different networks through the use of home agents,
foreign agents and mobile nodes.

In 1989, Charles E. Perkins and his colleagues at the IBM T.J. Watson
Research Centre in Hawthorn, New York, were working on the future of the
Internet. Though personal computers had become widely popular, laptops
and personal digital assistants (PDAs) were still few and far between.
Except at IBM.

In the computer giant’s labs, researchers developed a mobile wireless
device resembling PDAs such as today’s Palm Pilot or Handspring
Treo. To say they were ahead of the game would be an understatement: Palm’s
and Handspring’s products wouldn’t hit the market for about
another decade.

While wireless mobility was great in theory, there was one major practical
problem: getting the information sent to a mobile device via the Internet
when the device keeps moving. For stationary computers the problem doesn’t
exist because each computer has an IP address that remains stable, allowing
network routers to send emails and other information to their destinations
securely.

“But when we moved from one place to another with our prototype
device, all communication would break down,” said Perkins, explaining
that the existing Internet routers had no way of knowing where to send
the data packets without a stable IP address.

So Perkins set about to solve the problem.
His invention can be described by using the analogy of an office assistant:
When an executive is on a business trip, the office assistant knows where
the person is and forwards mails, phone calls and faxes directly to the
new address. When the executive arrives in another city, the assistant
simply updates the forwarding address. There is no interruption of service,
and the sender doesn’t even need to know that the addressee is actually
moving about the country.

Perkins’ solution works accordingly when a mobile device moves between
different networks. The communication infrastructure employs home agents,
foreign agents and mobile nodes. To ensure safety for use in a corporate
environment, Perkins used an encryption method, effectively blocking malicious
code by mathematically verifying messages that were intended for the addressee.
IBM patented the mobile IP technology in the United States in 1992 (US
5159592) and in Europe in 1996 (EP0483547).

The work on mobile IP, started by Perkins and expanded upon by other researchers
at Carnegie Mellon University and Columbia University, resulted in an
Internet Engineering Task Force (IETF) standard in 1996, which has been
continuously upgraded since.

“Mobile IP is widely implemented in CDMA networks in the US and
Asia,” said Peter McCann, Chairman of the IETF Mobility working
group and researcher at Lucent Technologies. Because IBM has not used the patent widely and most of the work has become
part of the IETF standard, it is hard to quantify the direct commercial
impact the invention has had. There are, however, no doubts as to the
innovative impact of the technology. Nextel, Motorola and Cisco, to name
a few, are using mobile IP in parts of their infrastructure.

Researchers agree that the technology has potential going forward: “Mobile
IP is being considered for future wireless networks,” said Vijay
Devarapalli, a Senior Research Engineer at Nokia who currently works with
Perkins. He added that Mobile IP is also used in some virtual private
networks (VPN) on corporate campuses. While the standard is employed in
a variety of applications in the United States, it is much less prevalent
in Europe. Microsoft doesn’t use the mobile IP standard, but there
are several Linux devices with mobile IP support on the market.

“It won’t be too long before PDAs and cell phones are going
to be pretty powerful computing devices, and when they run operating systems
with mobile IP support, it will have a big impact,” said Perkins.

After Perkins worked with IBM, he joined Sun Microsystems in 1997 and
is now a Nokia Fellow at the Nokia research centre in Mountain View, California.
Perkins, who holds a Master’s Degree in Mathematics from Columbia
University, has nine patents and five pending patent applications. He
won several IBM Invention Achievement Awards and a Service Award for contributions
to the Internet Architectural Board.

It’s no wonder his unofficial title is “Father of Mobile IP
Technology.”